What do I need to buy?

[the enemy]

Have a Specialised Sirrus Comp. Had it a few months now but I want drop bars and make it into a proper road bike. I dont particularly want to go and buy a new bike 1 because of cost and 2 this will be my little project.
It has a 3 chain ring on front and a 9 cassette on rear. Looking at Tiagra range but have not the 1st clue what to buy. I presume i just need new bars and brake levers-shifters?? Any help would be great. Thanks

 

[Theseus]

I am not familiar with the bike. Does it have V brakes? If so these may need replacing with road brakes like canti's. The amount of cable STI levers pull may not be sufficient to operate V's.

 

[the enemy]

It has 85mm linear pull